init commit

README.md

-# rp2040_gol_py
-
-
-
-## Getting started
-
-To make it easy for you to get started with GitLab, here's a list of recommended next steps.
-
-Already a pro? Just edit this README.md and make it your own. Want to make it easy? [Use the template at the bottom](#editing-this-readme)!
-
-## Add your files
-
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-
-```
-cd existing_repo
-git remote add origin https://gitlab.cba.mit.edu/quentinbolsee/rp2040_gol_py.git
-git branch -M main
-git push -uf origin main
+# Micropython game of life
+
+A very basic implementation of Conway's game of life for Micropython, accelerated by the numpy implementation provided by [ulab](https://github.com/v923z/micropython-ulab).
+
+![](doc/rp2040_gol_py.mp4)
+
+Using toroidal boundary conditions on the grid, one update cycle can be easily implemented:
+
+```py
+def step(grid):
+    """
+    computes one step of Conway's game of life on a toroidal 2D grid
+    """
+    count = np.zeros(a.shape, dtype=np.uint8)
+    count[:, :] = grid
+    # sum all 8 neighbors
+    count += np.roll(grid, 1, axis=0) + np.roll(grid, -1, axis=0)
+    count += np.roll(grid, 1, axis=1) + np.roll(grid, -1, axis=1)
+    count += np.roll(np.roll(grid, 1, axis=0), 1, axis=1) + np.roll(np.roll(grid, -1, axis=0), 1, axis=1)
+    count += np.roll(np.roll(grid, 1, axis=0), -1, axis=1) + np.roll(np.roll(grid, -1, axis=0), -1, axis=1)
+    # logical operator encoding the rules
+    return (count == 3) | (grid & (count == 4))
 ```
 
-## Integrate with your tools
-
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-## Collaborate with your team
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-
-***
-
-# Editing this README
-
-When you're ready to make this README your own, just edit this file and use the handy template below (or feel free to structure it however you want - this is just a starting point!). Thanks to [makeareadme.com](https://www.makeareadme.com/) for this template.
-
-## Suggestions for a good README
-
-Every project is different, so consider which of these sections apply to yours. The sections used in the template are suggestions for most open source projects. Also keep in mind that while a README can be too long and detailed, too long is better than too short. If you think your README is too long, consider utilizing another form of documentation rather than cutting out information.
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-## Name
-Choose a self-explaining name for your project.
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-## Description
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+On a rp2040 running at `250MHz`, one full update cycle on a `128 x 64` grid takes `~76ms`, including blitting the array to a 1306 OLED display through I2C. This is a refresh rate of `~13Hz`, enough for realtime applications.
 
-## Visuals
-Depending on what you are making, it can be a good idea to include screenshots or even a video (you'll frequently see GIFs rather than actual videos). Tools like ttygif can help, but check out Asciinema for a more sophisticated method.
+You can find the full code [here](./code).
 
 ## Installation
-Within a particular ecosystem, there may be a common way of installing things, such as using Yarn, NuGet, or Homebrew. However, consider the possibility that whoever is reading your README is a novice and would like more guidance. Listing specific steps helps remove ambiguity and gets people to using your project as quickly as possible. If it only runs in a specific context like a particular programming language version or operating system or has dependencies that have to be installed manually, also add a Requirements subsection.
 
-## Usage
-Use examples liberally, and show the expected output if you can. It's helpful to have inline the smallest example of usage that you can demonstrate, while providing links to more sophisticated examples if they are too long to reasonably include in the README.
+### Step 1: install Micropython
 
-## Support
-Tell people where they can go to for help. It can be any combination of an issue tracker, a chat room, an email address, etc.
+This implementation heavily relies on the ulab library. You can find a special version of Micropython with built-in ulab support [here](https://github.com/v923z/micropython-builder). For a generic rp2040 board, download [this](https://github.com/v923z/micropython-builder/releases/download/latest/RPI_PICO.uf2) file and place it on the device's flash storage after enabling the bootloader through a hard reset.
 
-## Roadmap
-If you have ideas for releases in the future, it is a good idea to list them in the README.
+### Step 2: install code
 
-## Contributing
-State if you are open to contributions and what your requirements are for accepting them.
+After installing Micropython on your device, interface with it using your favorite editor. If in doubt, you can use [Thonny](https://thonny.org/). Save the [main.py](./code/main.py) file on the device, as well as the [ssd1306.py](./code/ssd1306.py) library, with these exact filenames.
 
-For people who want to make changes to your project, it's helpful to have some documentation on how to get started. Perhaps there is a script that they should run or some environment variables that they need to set. Make these steps explicit. These instructions could also be useful to your future self.
+The default I2C pins are configured for a xiao rp2040:
 
-You can also document commands to lint the code or run tests. These steps help to ensure high code quality and reduce the likelihood that the changes inadvertently break something. Having instructions for running tests is especially helpful if it requires external setup, such as starting a Selenium server for testing in a browser.
+- SDA: 6
+- SCL: 7
 
-## Authors and acknowledgment
-Show your appreciation to those who have contributed to the project.
+You can change these if needed, in function `main()` in `main.py`.
 
-## License
-For open source projects, say how it is licensed.
+### Step 3: start code
 
-## Project status
-If you have run out of energy or time for your project, put a note at the top of the README saying that development has slowed down or stopped completely. Someone may choose to fork your project or volunteer to step in as a maintainer or owner, allowing your project to keep going. You can also make an explicit request for maintainers.
+By either pressing the run button in your editor or performing a reset of your device, the `main.py` should start and run the game of life.

code/main.py

+import ssd1306
+import framebuf
+from machine import SoftI2C, Pin, freq
+from ulab import numpy as np
+import random
+import time
+
+
+def step(grid):
+    """
+    computes one step of Conway's game of life on a toroidal 2D grid
+    """
+    count = np.zeros(a.shape, dtype=np.uint8)
+    count[:, :] = grid
+    # sum all 8 neighbors
+    count += np.roll(grid, 1, axis=0) + np.roll(grid, -1, axis=0)
+    count += np.roll(grid, 1, axis=1) + np.roll(grid, -1, axis=1)
+    count += np.roll(np.roll(grid, 1, axis=0), 1, axis=1) + np.roll(np.roll(grid, -1, axis=0), 1, axis=1)
+    count += np.roll(np.roll(grid, 1, axis=0), -1, axis=1) + np.roll(np.roll(grid, -1, axis=0), -1, axis=1)
+    # logical operator encoding the rules
+    return (count == 3) | (grid & (count == 4))
+
+
+def init_grid(grid):
+    height, width = grid.shape
+
+    # random initialization
+    for i in range(height):
+        for j in range(width):
+            grid[i, j] = random.getrandbits(1)
+
+
+def main():
+    freq(250000000)
+
+    i2c = SoftI2C(scl=Pin(7), sda=Pin(6))
+    display = ssd1306.SSD1306_I2C(128, 64, i2c)
+
+    width = 128
+    height = 64
+
+    a = np.zeros((height, width), dtype=np.bool)
+
+    init_grid(a)
+
+    i = 0
+    while True:
+        t1 = time.ticks_ms()
+        display.fill(0)
+        fb = framebuf.FrameBuffer(a.tobytes(), width, height, framebuf.GS8)
+        display.blit(fb, 0, 0)
+        display.show()
+        a = step(a)
+        t2 = time.ticks_ms()
+        i += 1
+        if i == 10:
+            print(f"dt: {time.ticks_diff(t2, t1)} ms")
+            i = 0
+
+
+if __name__ == "__main__":
+    main()

code/ssd1306.py

+# MicroPython SSD1306 OLED driver, I2C and SPI interfaces
+
+from micropython import const
+import framebuf
+
+
+# register definitions
+SET_CONTRAST = const(0x81)
+SET_ENTIRE_ON = const(0xA4)
+SET_NORM_INV = const(0xA6)
+SET_DISP = const(0xAE)
+SET_MEM_ADDR = const(0x20)
+SET_COL_ADDR = const(0x21)
+SET_PAGE_ADDR = const(0x22)
+SET_DISP_START_LINE = const(0x40)
+SET_SEG_REMAP = const(0xA0)
+SET_MUX_RATIO = const(0xA8)
+SET_COM_OUT_DIR = const(0xC0)
+SET_DISP_OFFSET = const(0xD3)
+SET_COM_PIN_CFG = const(0xDA)
+SET_DISP_CLK_DIV = const(0xD5)
+SET_PRECHARGE = const(0xD9)
+SET_VCOM_DESEL = const(0xDB)
+SET_CHARGE_PUMP = const(0x8D)
+
+# Subclassing FrameBuffer provides support for graphics primitives
+# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html
+class SSD1306(framebuf.FrameBuffer):
+    def __init__(self, width, height, external_vcc):
+        self.width = width
+        self.height = height
+        self.external_vcc = external_vcc
+        self.pages = self.height // 8
+        self.buffer = bytearray(self.pages * self.width)
+        super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
+        self.init_display()
+
+    def init_display(self):
+        for cmd in (
+            SET_DISP | 0x00,  # off
+            # address setting
+            SET_MEM_ADDR,
+            0x00,  # horizontal
+            # resolution and layout
+            SET_DISP_START_LINE | 0x00,
+            SET_SEG_REMAP | 0x01,  # column addr 127 mapped to SEG0
+            SET_MUX_RATIO,
+            self.height - 1,
+            SET_COM_OUT_DIR | 0x08,  # scan from COM[N] to COM0
+            SET_DISP_OFFSET,
+            0x00,
+            SET_COM_PIN_CFG,
+            0x02 if self.width > 2 * self.height else 0x12,
+            # timing and driving scheme
+            SET_DISP_CLK_DIV,
+            0x80,
+            SET_PRECHARGE,
+            0x22 if self.external_vcc else 0xF1,
+            SET_VCOM_DESEL,
+            0x30,  # 0.83*Vcc
+            # display
+            SET_CONTRAST,
+            0xFF,  # maximum
+            SET_ENTIRE_ON,  # output follows RAM contents
+            SET_NORM_INV,  # not inverted
+            # charge pump
+            SET_CHARGE_PUMP,
+            0x10 if self.external_vcc else 0x14,
+            SET_DISP | 0x01,
+        ):  # on
+            self.write_cmd(cmd)
+        self.fill(0)
+        self.show()
+
+    def poweroff(self):
+        self.write_cmd(SET_DISP | 0x00)
+
+    def poweron(self):
+        self.write_cmd(SET_DISP | 0x01)
+
+    def contrast(self, contrast):
+        self.write_cmd(SET_CONTRAST)
+        self.write_cmd(contrast)
+
+    def invert(self, invert):
+        self.write_cmd(SET_NORM_INV | (invert & 1))
+
+    def show(self):
+        x0 = 0
+        x1 = self.width - 1
+        if self.width == 64:
+            # displays with width of 64 pixels are shifted by 32
+            x0 += 32
+            x1 += 32
+        self.write_cmd(SET_COL_ADDR)
+        self.write_cmd(x0)
+        self.write_cmd(x1)
+        self.write_cmd(SET_PAGE_ADDR)
+        self.write_cmd(0)
+        self.write_cmd(self.pages - 1)
+        self.write_data(self.buffer)
+
+
+class SSD1306_I2C(SSD1306):
+    def __init__(self, width, height, i2c, addr=0x3C, external_vcc=False):
+        self.i2c = i2c
+        self.addr = addr
+        self.temp = bytearray(2)
+        self.write_list = [b"\x40", None]  # Co=0, D/C#=1
+        super().__init__(width, height, external_vcc)
+
+    def write_cmd(self, cmd):
+        self.temp[0] = 0x80  # Co=1, D/C#=0
+        self.temp[1] = cmd
+        self.i2c.writeto(self.addr, self.temp)
+
+    def write_data(self, buf):
+        self.write_list[1] = buf
+        self.i2c.writevto(self.addr, self.write_list)
+
+
+class SSD1306_SPI(SSD1306):
+    def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
+        self.rate = 10 * 1024 * 1024
+        dc.init(dc.OUT, value=0)
+        res.init(res.OUT, value=0)
+        cs.init(cs.OUT, value=1)
+        self.spi = spi
+        self.dc = dc
+        self.res = res
+        self.cs = cs
+        import time
+
+        self.res(1)
+        time.sleep_ms(1)
+        self.res(0)
+        time.sleep_ms(10)
+        self.res(1)
+        super().__init__(width, height, external_vcc)
+
+    def write_cmd(self, cmd):
+        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
+        self.cs(1)
+        self.dc(0)
+        self.cs(0)
+        self.spi.write(bytearray([cmd]))
+        self.cs(1)
+
+    def write_data(self, buf):
+        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
+        self.cs(1)
+        self.dc(1)
+        self.cs(0)
+        self.spi.write(buf)
+        self.cs(1)